DE1808650A1 - Fuel injector - Google Patents

Description

R. 9313
November 8, 1968 Su / Wa

Attachment to

Patent and

utility model registration

ROBERT BOSCH GMBH, 7 Stuttgart W, Breitscheidstrasse 4

Fuel injector

The invention relates to a fuel injection device for multi-cylinder internal combustion engines with an injection pump, at least one cylinder of their pump work frustration the internal combustion engine is supplied with a larger amount of fuel (main amount) through a pressure line (main line), from the to at least one other cylinder for simultaneous delivery of a smaller amount an auxiliary line branches off, the two cylinders by a working cycle given by the offset of the crankshaft throws work offset against each other.

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00982S / 0701

Robert Bosch GmbH R. 9313 Su / Wa

Stuttgart

In such a fuel injection device, the amount of fuel to be burned is injected in two parts, whereby a particularly good combustion is achieved.

In a known fuel injection device of this type (see American patent specification 3,216,407) opens the auxiliary line in the main line of the cylinder operating offset by half a work cycle. At a other known fuel injectors (see German patent specification .1 212 782) are two main lines

a
lines that lead to two cylinders working offset by half a work cycle, connected to one another by an auxiliary line. In the auxiliary lines of both known fuel injection devices are throttle devices ^! arranged so that the amount flowing through the auxiliary line is smaller than the main amount as desired.

These fuel injection devices have the disadvantage that a desired exact division of the amount of fuel either as a constant quantity ratio or as a ratio at which a quantity should remain constant, is not achieved can be, as the fuel from one main line over that of her. branching auxiliary line into another Main line arrives in which at this point in time from the pump connection forth is not promoted, so that the liquid column located therein yields elastically. Depending on the engine speed according to the. Delivery strokes of the injection pump per unit of time affects this elasticity more or less, whereby the proportion is influenced.

009826/0701

Robert Bosch GmbH Stuttgart

R. 9313 Su / Wa

The invention is based on the object of avoiding the disadvantage mentioned. This object is achieved according to the invention solved in that the staggered injection of the in a cylinder or in the intake manifold of this cylinder larger amount compared to the smaller amount takes place via separate valves, with - ^ larger and the smaller amount can be injected through the same injection opening.

It has been shown that it is advantageous if the quantitative ratio rather, the smaller amount does not increase at all or increases less than the larger amount is not constant. One corresponding embodiment of the subject matter of the invention provides that the smaller amount in a manner known per se (see DAS 1 252 002) by a spring which can be displaced under the pressure of the fuel supplied against the force eir .. * Metering piston is determined, which has a stop to determine its rest position and limit its path.

In a particular embodiment, the surfaces acting in the opening direction bind to the valve needles and the force of the springs acting in the closing direction on the valves intended for the larger amount compared to those for the smaller amount certain valves are chosen so that first the valve needle lifts off the seat, in whose pressure chamber the one displaced by the metering piston Smaller amount flows in and the pressure is only applied after the metering piston is in contact with the stop that limits its path of the fuel in the corresponding main line is able to rise so high that the valve needle for the larger amount opens. This ensures that in every operation

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Robert Bosch GmbH R. 9313 Su / Wa

Stuttgart.

stood the smaller amount being injected.

In a preferred embodiment of the subject matter of the invention, all the metering pistons are in one control unit, in particular arranged axially parallel, with the adjustable stop which determines the rest position by a common smaller amount can be changed. This allows the division ratio of the quantities in any desired way. The common stop can, for example, through the injection timing adjuster or the speed controller of the injection pump or other electrical or hydraulic ones Means are operated. Such a control device can also be used in injection systems in which a there is only one valve for the larger and smaller quantities of fuel supplied to a cylinder.

The fuel injection device according to the invention is particularly advantageous used in internal combustion engines with spark ignition, the first being the larger amount and if possible later the smaller quantity (ignition quantity) is injected into the same cylinder. Here the ignition amount is close the spark plug injected. The part injected first has time to evaporate or to mix well with the combustion air mix, while the ignitability of the fuel-air mixture is achieved or improved by the second part.

Various embodiments of the subject invention are shown partially simplified in the drawing. They show in detail:

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009826/0701

Hobert Bosch GmbH R. 9313 Su / Wa

Stuttgart

Pig. 1 a fuel injection device for a four-cylinder engine,

Pig. 2 a fuel injection device for a six-cylinder engine,

Pig. 3 a fuel injector for a Eight cylinder engine,

4 shows an injection nozzle in longitudinal section with a built-in metering piston,

Pig. 5 a fuel injection device for a four-cylinder engine with a control unit that accommodates the metering pistons, ' _:

Pig. 6 is a diagram in which a possible change by the control unit in the ratio of the larger Amount is shown as the smaller amount,

Pig. 7 that in Pig. 5 control device shown in axial section along the line VII-VII in Pig. 8th,

Pig. 8 is a cross-section through that in Pig. 5 control device shown according to the line-VIXX ^ VIII in Pig. and

Pig. 9 one for those in Pig. 5 illustrated fuel injection device suitable injector.

As shown in simplified form in Figures 1 to 3, leading from an injection pump 10 depending on a pressure line (main line) to each cylinder of an internal combustion engine by the pressure lines 11 branch off in the vicinity of the Brennkräft- aaeohine 12 help lines 13 from which au cylinders dee motor

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009825 / 07.01

Robert Bosch GmbH R. 9313 Su / Wa

Stuttgart

lead by a given by the angular offset of the cranks of the crankshaft 14 work cycle against each other work offset.

The fuel injector shown in Fig. 1 is intended for a four-cylinder engine with cylinders 1, 2, 3 and 4, with the firing order corresponding to the angular offset the throws of the crankshaft in the order of the cylinders is 1.3 »4» 2. First the larger amount should (Main quantity) and later the smaller quantity (ignition quantity) can be injected. However, both quantities must be used during the Duty cycle of the cylinder to be injected. Since the crankshaft throws of this four-cylinder engine are in lie one level, the ignition quantity must be injected when the crankshaft 14 has been since the injection Has turned the main quantity further by 180 °. As a result, are In this engine, the two cylinders are always connected by a line system consisting of a main and an auxiliary line, whose firing order is 180 ° crankshaft angle in succession, i.e. the cylinder to which the cylinder fires first Auxiliary line 13 leads and after 180 ° rotation of the crankshaft the cylinder of the same line system to which the Main line 11 leads. They branch off the main lines leading to cylinders 1, 2, 3 and 4 in the corresponding order the auxiliary lines leading to cylinders 2, 4, 1 and 3 away.

In the example shown in Fig. 2 Fuel injection device for a six-cylinder engine, the injection of the smaller quantity follows the larger amount after the crankshaft has rotated 240 ° "The greater this time," span zwisohen injection of greater amount and ·

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009826/0701

Robert Bosch GMBH . R. 9313 Su / Wa

Stuttgart

Injection of the smaller amount, the more time is available for fuel preparation and the more the combustion is better. In the embodiment of the six-cylinder engine, the firing order is in the order the cylinder 1,5,3,6,2,4. Here branch from the to the cylinders 1,2,3 as well as 4,5 and 6 leading pressure lines in the corresponding order to the cylinders 2,3,1 as well as 6,4) and 5 leading auxiliary lines.

In Pig. 3 shown fuel injector for an eight-cylinder engine, the angle at which the crankshaft after injection of the larger quantity is up to Injection of the smaller amount is rotated, advantageously 270 °. Here the larger amount of fuel is injected and the smaller amount is injected shortly before the end of the compression stroke. from the main lines leading to the cylinders 1 to 8 of the internal combustion engine 12 branch off the auxiliary lines, which are in the corresponding sequence to cylinders 5,3,1,2,7,8,6,4 to lead.

The larger and smaller quantities are injected into each engine cylinder via separate injection valves and via hydraulically completely separate systems. Both Injectors can be housed in a single body, as in Pig. 4 shown.

A nozzle body 20 is clamped to a nozzle holder 22 by means of a union nut 21. In the nozzle holder 22 has two terminal holes 23 _f 24 are provided, of which the bore 23

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Robert Bosch GMBH . R. 9313

Stuttgart

for connecting an auxiliary line 13 and the hole 24 to ' Connection of a main line 11 is used.

In an axial bore 25 in the nozzle body 20, a hollow needle 26 is axially displaceable and guided as tightly as possible, -die with the nozzle body 20 delimits a pressure chamber 27, furthermore a valve cone 28 is provided on the hollow needle 26, the one in the closed state on iron on the barrel 1 arranged inner cone 29 is pressed and with this forms a valve seat 50 »coaxial with the axial bore 25 a bore 31 is arranged in the nozzle holder 22, whose Diameter is slightly smaller than the diameter of the axial bore 25. This hole 31 is with an outer connection hole connected and takes on a closing spring 32, which has a, in the hollow needle 26 guided spring plate 33 the hollow needle on the valve seat 30 presses. Me by the difference in the diameter of the bores 25 and 31 formed shoulder on Nozzle holder 22 serves as a stop and stroke limiter for the hollow needle 26.

For the connection bore 23 a channel 34 leads to a bore 35 in the nozzle holder, in which a metering piston 36 is axially displaceable and with play against a return spring 37. · The metering piston 36 contributes to its Stroke limitation a locking pin 38. fön the bore 35 then a channel 39 leads to the pressure chamber 27 of the hollow needle 26e

In a hollow needle 26 there is a valve needle 4 ″ i can be displaced in the direction of flow against a closing spring 42 arranged «The closing spring 42 stüfcsi, on the one hand ■

Q0SS2E / Q70

Robert Bosch GmbH - R.9313 Su / Wa

Stuttgart

on a shoulder in the bore 49 of the hollow needle 26, engages via a Pederteller 43 on the valve needle and presses a cone 45, which forms the transition to a valve needle head 44, onto a corresponding inner cone of the hollow needle 26.

In order to obtain a completely separate injection of larger and smaller quantities, the sealing cone 28 of the hollow needle merges into an annular groove 46 which is in constant communication with the injection openings 47 arranged in the nozzle body. The hollow needle 26 is tightly guided in the nozzle body 20 ^{with a cylindrical section 26 f} arranged following the annular groove 46.

The injection valve described works in the example after Pig. 1 as follows «

The larger amount of fuel, which first reaches the injection valve from the injection pump via the main line, flows via the bore 31 into the bore 25 and from there via Pederteller 33 or through inclined bores 48 in the hollow needle 26 and the bore 49 into the one between the hollow needle 26 and the valve needle 41 formed pressure chamber 50. As soon as a sufficiently high pressure has been reached, ie after, as will be explained in more detail later, the smaller amount passed through the same line system is injected into the cylinder 2, the valve needle 41 lifts with its cone 45 from the seat and the The main amount of fuel is injected into cylinder 1.

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009825/0701

Robert Bosch GMBH --_ . H. 9313 Su / Wa

Stuttgart

The smaller amount of fuel arrives later via the auxiliary line 3 from the other pipe system described above Via the channel 34 into the bore 55, "at a sufficiently high pressure, the metering piston 3" S counteracts the return spring 37 moved until its stop pin 38 ends the path »The fuel displaced by the metering piston 36 passes through the Channel 39 into the pressure chamber 27 and after lifting the hollow needle 26 from its seat 30 via the llsgnut 4β and the fuel orifices 4 · 7 into the combustion chamber of cylinder 1. The into the Pressure chambers 49 and 27 acting in the opening direction surfaces on the valve needle 41 and hollow needle 26 and the closing force of the springs 32 and 42 are selected such that the valve needle 41 only then from Sits; takes off when the tob. the same Line system thus located in the corresponding other injection valve hollow needle 25 already after injection the smaller crowd rests on their seat «Between two The metering piston 36 is injected by the spring 37 pushed into its starting position * whereby the spring 37 receiving space through the play between Zu-Bv .-. SskQlben 36 and hole 35 fills the gap formed with fuel again.

Bfci of the in fig, 5
direction, the eggs, in Fig _a 1 represented "is, iii the auxiliary-ivleitungen" 53 geschallt sin gssisiasaaes controller 51st Bie injection pump 10, liier represented as Reihesipumpe, iet with a Drslisahlregler 52, with a Eogülstauge 55 as well as with a Spritsirersteller 54 The control gear 53 is via a gear length 55 with a control bolt from the control unit 51

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Robert Bosch GmbH R. 9513 Su / Wa

Stuttgart

56 connected. Like the one in Pig. _{6, the smaller fuel quantity Q 2 can} be changed by the control unit 51, which receives the metering piston 36, whereby the ratio between the larger and smaller quantity can be set as desired. In the diagram, the delivery rate Q is plotted on the ordinate and the path 8 of the adjusting bolt 56 is plotted on the abscissa. Particularly in internal combustion engines with spark ignition, in which the smaller amount is injected into the area of the spark plug in order to obtain a well-igniting mixture, it is desirable that the smaller the amount Q ₂ decreases as the injected amount Q ^ increases, until then at full load the smaller or ignition quantity Q ₂ = O. As can also be seen from the diagram, the main _{amount Q 1} = 0 at idle speeds, whereas the smaller amount Q ₂ has reached its maximum.

As shown in Fig. 5, when the control rod 53 is moved in the direction of full load, which is shown by the arrow is displaced via the linkage 55 of the adjusting bolt 56 of the control unit 51 so that the smaller injection quantity decreases. The adjustment of the adjusting bolt 56 could, however also take place by other means, hydraulically, pneumatically or electrically, whereby as adjustment variables instead of the control rod 53, other elements measuring an engine operating variable could be used.

The control device shown in sections in FIGS has a body 58 with axes distributed parallel to the axis

00982S / C701

Robert Bosch GmbH R. 9513 Su / Wa

Stuttgart

Bores 59 »which receive the metering pistons 36. With the Metering piston 56 is in each case a valve part 60 against the Force of the return spring 37 shifted to the termination of the stroke serving as a stop is pressed onto a valve seat 61 and thus blocks the flow. Her metering piston is guided in the bore 59 with play so that an annular gap is created through which the space in front of the metering piston, from which the fuel is fed through the metering piston

Injection is displaced, can refill with fuel between two injections as long as the spring pushes the metering piston 56 back into its starting position. Upstream of the metering pistons, the bores 59 are connected via ladial bores 64 to the sections of the auxiliary lines 15 branching off from the main lines 11. BIe sections of the auxiliary lines 13 leading to the injection valve are connected to the valve seat part 61. The direction of the current is shown by arrows.

The rest or starting position of the metering piston 36 is through Stop bolts 62 are determined, which are axially displaceable and sealingly guided in the bores 59. The stop bolts 62 have a tapered section 63 towards the metering piston 10 / to allow the fuel entering through the bores 64 not to hinder. The stop bolts 62 protrude beyond the end face of the body 58 out into a space 66 one the housing head 6 covering the body 58? ”Who is hardly 66 through a bore 68, which leads to a leakage channel that is not exposed leads, relieved of pressure. The stop pins 62 support on a plate 69, which is fixed with the adjusting bolt 56 are connected. If the plate 69 is axially displaced over the adjusting bolt 56, the stop bolts 62 become with it

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Robert Bosch GmbH R. 9313 Su / Wa

Stuttgart

shifted, whereby the starting position of the metering piston 36 changes before the smaller amount is injected. By changing this starting position, the possible through the Stops 16 specific stroke of the metering piston 36 also changed and thus the smaller amount to be injected.

In Pig. 9 shows a nozzle which works together with the control unit 51. The main difference from that in Pig. 4 consists in the fact that the metering piston is no longer arranged in the nozzle itself but in the control unit. A nozzle body 71 is clamped to a nozzle holder 73 by a union nut 72. Valve needles 74 and 75, which open in the direction of flow against the force of closing springs 76 and 77, are arranged in bores in the nozzle body 71. The Pedern-74 and 77 are supported on the one hand on a step of the bore in the nozzle body 71 and on the other hand on Peder plates 78, which are connected to the valve needles by retaining rings. The spaces accommodating the Peders 76 and 77 also serve as pressure spaces.

The puncture is as follows

For injection of the smaller amount of fuel flows from the ZumeBsteuergerät 51 through the corresponding section of the guide line 13 to a connecting bore 79 in the nozzle holder 73. From there, the fuel passes through a passage 80 to the pressure chamber of the valve needle 74 * for the injection of the main amount gelarigt the fuel on the Main line 11 and a connection hole 81 in the nozzle holder and one

009825/0701

Robert Bosch GmbH R. 9313 Su / Wa

Stuttgart '■

Channel 82 into the pressure chamber of the valve needle 75. The buttons of the valve needles 74 and 75 and the corresponding im Valve seats arranged in the nozzle body 71 are designed in such a way that that the smaller amount injected via the valve needle 74 has a cone with a large spray angle, " while the over the valve needle .. 75_leing ^ sp r it ate main amount has a spray cone with a small angle. This ensures that the larger amount is deep in the Into the engine cylinder, the smaller amount being injected flat under the spark plug.

However, the fuel injection device described takes place in no way only used for direct injection into the engine cylinder, but also applies ■ In the case of injections into the intake manifold, e.g. directly in front of the intake valve on the cylinder head. For engines with Prendignition is also possible in such a way that the main amount is injected into the intake manifold, while the ignition amount is injected directly into the engine cylinder in front of the spark plug »

The fuel injection device described has in particular also have the advantage that they operate with excess air permitted. Air surplus improves, but at part load the overall efficiency and reduces the proportion of harmful. Exhaust gas components. As a result of this possibility the injection system is simplified because the throttle valve and the control unit for assigning the air filling and dropping can. . ".-

Claims (15)

Robert Bosch GmbH R. 9313 Su / Wa Stuttgart claims 1. Fuel injection device for multi-cylinder internal combustion engines with an injection pump, at least one cylinder of the internal combustion engine of the pump working chamber a larger amount of fuel (main amount) is supplied through a pressure line (main line), from which to at least an auxiliary line branches off from another cylinder for the simultaneous delivery of a smaller amount, the two cylinders by a working cycle given by the offset of the crankshaft throws work offset, characterized in that the in a cylinder or in the intake manifold of this cylinder Timed injection of the larger amount compared to the smaller ^ amount via separate Valves (26,41) takes place. 2. Fuel injection device according to claim 1, characterized characterized in that the larger and the smaller amount is injected through the same injection opening. 3. Fuel injection device according to claim 1 or 2, characterized in that the smaller amount in 009825/0701 " ¹⁶ " Robert Bosch GMBH . R. 931.3 Su / Wa Stuttgart known way by a pressure of the supplied fuel against the force of a spring (37) displaceable metering piston (36) is determined to Determination of its rest position and limitation of its path each has a stop (38) " 4. Fuel injector according to claim 3 $ thereby characterized ,, that the metering piston (36) is known per se Way in the injection valves (20,22) are arranged 5. Fuel injector-for multi-cylinder internal combustion engines with an injection pump, from its pump working space at least one cylinder of the internal combustion engine a larger amount of fuel (main amount) through a pressure line (Main line) 'is supplied from which to at least another cylinder ssur simultaneous promotion of a - 'smaller amount branches off an auxiliary line, the
both cylinders operate offset from one another by a working cycle given by the cross-linking of the crankshaft throws, in particular according to one of claims 1 or 2, characterized in that the smaller amount -17- 00982S / 0701 ν · mmmirr, "; s * SU Robert Bosch GmbH R. 9313 Su / Wa Stuttgart in a manner known per se by a force of a spring under the pressure of the supplied fuel (37) displaceable metering piston (36) is determined, the one stop (38) for determining its rest position and limiting its path. having. 6. Fuel injection device according to claim 5, characterized characterized in that the metering pistons (36) are arranged in a control unit (51) »in particular axially parallel and the smaller amount can be changed by a common adjustable stop (69) which determines the rest position. 7. Fuel injection apparatus according to claim 6, characterized in that the rest position-determining stopper consists of bolts (62) and a plate (69), said each metering spool (36) ~~., Eordneten bolt (62) axially displaceable and as close as possible are guided in the bores (59) receiving the metering pistons (36) and are supported outside the housing (58) containing these bores (59) on the plate (69) which is adjustable in the axial direction of the bolts (62) by operational means . -18- 009826/0701 Robert Bosch GmbH R. 9313 Su / Wa ' Stuttgart 8. Fuel injection device according to one of the preceding Claims, characterized in that the pressure chambers (27, 4-9) counter to the force of closing springs (32, 42) movable valve needles (26, 41) controlling the passage of the valves, arranged in a nozzle body (20) and are completely hydraulically separated from each other for the larger and smaller quantities. 9 »Fuel injection device according to one of the preceding Claims, characterized in that in a manner known to eich "the one valve needle (41) of a Hollow needle (26) is received, with one valve seat (46) between valve needle (41) and hollow needle (26), the other is arranged between the hollow needle (26) and the nozzle body (20) 10. Fuel injection device according to one of claims 3 bie 9 9 characterized '»that the surfaces acting in the opening direction on the valve needles (26,41) and Me force of the springs (32,42) acting in the closing direction on the intended for the larger amount Valves 009825/0701 Robert Bosch GmbH R. 9313 Su / Wa Stuttgart (41) are selected in relation to the valves (26) intended for the smaller amount so that the valve needle is first (26) lifts off the seat (30), into whose pressure chamber (27) the smaller amount displaced by the metering piston (36) flows and the pressure of the Fuel in the corresponding main line (11) so able to rise high that the valve needle (41) opens for the larger amount. 11. Fuel injection device according to one of the claims to 10, characterized in that a movable valve part (60) is displaced with the metering piston (36), the after the end of the stroke is pressed sealingly onto a valve seat (61). 12. Fuel injection device according to one of the claims 3 to 11, characterized in that between the metering piston (36) and the cylinder bore receiving it (59) a specific game is provided. 13 · Fuel injection device according to one of the preceding Claims, characterized by the application -20- 009825/0701 Robert Bosch GmbH R. 9313 Su / Wa Stuttgart in internal combustion engines with spark ignition, ala first the larger amount and as late as possible the smaller Quantity (ignition quantity) is injected into or in front of the same cylinder. 14 · Fuel injection device according to claim 13 »characterized characterized that with offsets of the crankshaft throws of 3 x 120 ° or 4 x 90 ° etc. the ignition quantity only after 2 χ 120 ° or 3 x 90 ° etc. after the main quantity is injected into the same cylinder. 15. Fuel injection device according to claim 13 or 14, characterized in that the ignition quantity is injected in the vicinity of the spark plug. P. 00 9825/070 1